By the end of this week, the Republican Party will have officially nominated Donald Trump as its presidential candidate and presented its opening shot in the general election race that culminates with U.S. voters making their choice November 8.

In anticipation of that nomination, several hundred Donald Trump supporters and opponents held rallies a kilometer apart as the four-day Republican National Convention opened Monday in the northern city of Cleveland, Ohio.

There was a heavy police presence on the streets, with officers from other states joining their colleagues in Cleveland. The deadly truck attack in France and the ambush killings of five police officers earlier this month in Dallas and three more in Baton Rouge, Louisiana, over the past weekend have heightened fears of bloodshed in Cleveland.

Security is to be the focus of the first day of the convention, along with immigration.

Speakers include the former governor of the border state of Texas, Rick Perry; the mother of an American killed in Benghazi, Libya; several immigration reform advocates; former New York Mayor Rudy Giuliani; and Trump's wife, Melania.

In an interview with CBS' 60 Minutes broadcast Sunday night, Trump answered a question about the state of the world with an answer that is a likely preview of criticisms that will be directed this week at President Barack Obama and Democratic candidate Hillary Clinton.

'We need strength'

"We need strength," Trump said. "Obama's weak, Hillary's weak. And part of it is, a big part of it, we need law and order. We need strong borders."

Trump has proposed building a wall along the U.S.-Mexican border, as well as banning Muslims from entering the country. He softened slightly on the Muslim ban in Sunday's interview, suggesting he would focus more on people's country of origin.

"There are territories and terror states and terror nations that we're not gonna allow the people to come into our country. And we're gonna have a thing called 'extreme vetting,'" he said.

Trump has repeatedly said he opposed the 2003 invasion of Iraq, while also pointing to Clinton's vote in the U.S. Senate backing the war. Trump's running mate, Indiana Governor Mike Pence, also voted to support the war while a member of the House of Representatives.

"I don't care," Trump said when asked about Pence's vote. "It's a long time ago. And he voted that way and they were also misled. A lot of information was given to people."

He said he does not give the same leeway to Clinton for her vote.

Not true conservatives

Johanna Bulein, a Trump supporter who traveled to Cleveland from the state of Tennessee, said those who do not support Trump are not "true conservatives."

"They are traitors as far as I am concerned," she told VOA. "They either get behind him, or they get the hell out of the way."

Medea Benjamin, co-founder of the pacifist group Code Pink, said the group was in Cleveland protesting Trump because of his "racist rhetoric" and "the kind of hate and fear that he's been propagating."

"We think it's very dangerous for this country," she told VOA. "We think it's not the kind of country we want to live in, nor the way we want to relate to the people around the world."

Presidential nomination

Trump will accept the nomination Thursday after besting 16 other candidates during the primary election season.

Republican Party chairman Reince Priebus said Sunday he believes Trump's acceptance speech will give voters a chance to view him as a plausible leader.

While some leaders, including House Speaker Paul Ryan, are giving addresses at the convention, others such as former presidents George H.W. Bush and George W. Bush, and former presidential nominees John McCain and Mitt Romney are not attending the event.

Democratic convention

Clinton will accept the Democratic nomination at the party's convention next week in Philadelphia, Pennsylvania.

Three new polls released Sunday show Clinton leading Trump. The ABC News/Washington Post poll put Clinton ahead 47 to 43 percent, while NBC News and The Wall Street Journal pegged the race at 46-41 and CNN/ORC International at 49-42.

VOA Russian service reporter Natasha Mozgovaya contributed to this report from Cleveland.